Hillary Clinton is applauded by the actress Jamie Lee Curtis as she arrives at a United Food and Commercial Workers International Union rally in Buena Park, California last week.
Photograph: Lucy Nicholson/Reuters

The week that Donald Trump finally sealed the Republican presidential nomination ought to have been a triumphant one for Hillary Clinton. With a final few delegates nudging him past the official finishing line on Thursday, here at last was the candidate that Democrats always dreamed of running against: unpopular, undisciplined and ostensibly unelectable in November’s general election.

Yet in the Alice in Wonderland world of American politics in 2016, nothing is what it seems. Clinton supporters would instead have to stomach six impossible things before the week was out.

The first was the sight of the former secretary of state falling behind her Republican opponent in an average of national opinion polls. Though by a wafer-thin – and probably temporary – margin, the breaching of this symbolic threshold could yet become self-fulfilling if it normalises the once unthinkable prospect of a Trump-themed White House.

Then came a damning report by an independent inspector at the Department of State, who contradicted her claims that she had been allowed to use a private email server for official business while serving as the nation’s chief diplomat. Once again, things were not quite as simple as they appeared, and Clinton allies argue that the report also shows other former secretaries of state up to the same tricks. But only one of them is running for president. With the FBI still investigating whether she broke federal law, this is an old wound that could reopen again before the contest is over.

Some Democrats, such as progressive champion Elizabeth Warren, show signs of trying to rally around their beleaguered team captain, yet the ongoing FBI investigation also complicates the ability of the party’s most influential cheerleader to come to the rescue. At a press conference in Japan, the normally loquacious Barack Obama flat out refused to take a question from a journalist asking whether the email scandal undermined Clinton’s “trustworthiness”.

In part, the ringing non-endorsement reflects the president’s need for political as well as legal neutrality. For perhaps the biggest surprise of the race so far is that it is the Democratic party – not the Republicans, who were once forced to choose from 17 candidates – that is still officially undecided on its nominee. Bernie Sanders might be far enough behind in the delegates race for Clinton to plausibly declare herself the victor already, but he is putting up a surprisingly spirited fight on the final sprint to the finishing line.

Another surprise blow to team Clinton last week was new opinion polling in California, where the penultimate and largest Democratic primary takes place on 7 June. It shows Sanders virtually neck and neck among voters and has forced Clinton to schedule extra appearances to try to avoid the humiliating prospect of winning the national nomination race on the same day as she loses the largest state.

To make matters worse, Sanders responded to Clinton’s decision to pull out of a scheduled televised debate by taking up a (since also rescinded) offer to face Donald Trump instead. Though establishment Democrats fume at the disloyalty of such a stunt, few doubt it would draw giant audiences. Somewhat less attention was drawn to the final shock news last week: a federal investigation into campaign contributions to long-time Clinton confidant and the governor of Virginia, Terry McAuliffe. With the FBI now investigating both the candidate and an elected official with perhaps the closest ties to her family, Trump may yet have more ammunition for his “crooked Clinton” taunts than even he expected.

Whether these surprise developments in a week in May add up to lasting consequences in November is, of course, another matter. Some strategists in Washington believe that Clinton should simply sit tight and ride out a storm that will pass quickly.

“The polls are showing the race effectively tied, but Trump and Clinton are at very different points in their campaign,” says veteran political analyst Charlie Cook. “The Republicans have come back in line faster than a lot of people thought, but Sanders will be out of her way in a week and a half, and her natural lead will return to three or four points. In November, it is not going to matter a whit if he won California. Bernie Sanders is going to be in her rearview mirror very, very soon.” He argues that scrutiny can only get harder for Trump, while Clinton may have been through the toughest phase already. “The worst things that could happen are largely behind her. If the justice department was going to charge her, it would probably have done so by now,” adds Cook. “I would rather be her [than Trump]. There are too many things that have to go right for him. I don’t think she’s in a terribly challenging place.”

Certainly, for Trump’s national poll improvements to bear fruit requires some heroic assumptions about the state-level contests that actually decide presidential elections.

Not only would the New York billionaire probably have to transform previously safe Democratic territory in the rust belt, such as Pennsylvania and Michigan, as well as the more finely balanced Ohio, but he would also have to stop Clinton dominating in more diverse states such as Virginia and Colorado and possibly winning back Arizona and Georgia from Republicans.

But other experts, such as Larry Sabato of the Center for Politics at the University of Virginia, worry that Clinton’s struggle to conclude the Democratic race could make for a bumpy party convention that will yet dent her prospects in November.

“How she handles Sanders is key. If she does it skilfully, it will be crucial to motivating younger voters, who are very hard to get out to vote if they are not enthusiastic,” says Sabato. “If he wins California, it guarantees he will go forward to the convention trying to turn every last delegate – and it could be very damaging for her. It is a turning point.”

Just as importantly, he argues, Clinton needs to go on the offensive and set her own agenda over the next few weeks. “Some things she can’t control. She can’t control the FBI. She started that ball rolling and will have to live with the consequences,” adds Sabato. “She has to demonstrate how she is going to attack Trump. They are all over the map at the moment because there is an embarrassment of riches, but there is devilry in that, in a way.” Right now, most pundits agree that it all makes for a noisy political environment in which it is hard to judge who is really winning on a day-to-day basis.

Kathleen Hall Jamieson, professor of communications at the Annenberg Public Policy Center at the University of Pennsylvania, believes the best approach is for Clinton to try to define her own news agenda rather than respond to that of her critics.

“The news environment matters. The email news could have been much worse if it had fallen in a quieter week. She benefited last week from the fact that there has been a cluttered news environment,” she says.

But Jamieson, who founded FactCheck.org to help hold politicians to account, is scathing of the tactics adopted by team Clinton over the emails, which she believes distorts the degree to which the rules have changed since previous secretaries of state were in office. “[Clinton] is making the best she can of it, but she is doing it by misrepresenting the facts. It would be smarter not to offer misleading inferences,” she says.

Beyond all else, this suggests it is the FBI, rather than Sanders or Trump, that could really spoil the party. “California is not likely to come back to haunt her,” concludes Jamieson. “The damaging thing is the report by the state department and how it fits in the ongoing narrative. This speaks to a central part of her campaign, her experience, and calls into question her judgment. The question now is what is the next shoe to drop.”